When you diffuse essential oils, you're probably getting ready for a relaxing, zen moment with yourself. The last thing on your mind is the thought that essential oil diffusers can be a safety hazard that could cause chemical burns. In a recent Facebook post, UK-based Emily Smith shared her story to warn everyone of this potential.

On a recent Saturday evening, Smith was using a popular electric diffuser filled with some patchouli oil when it sprayed some vapor on her face.

A few hours later, she stood up to fix the fire and her face began to sting more and more until she realized it must be a burn.

She ran her face under cool water and called 111 (the UK version of 911) and described her "red, un-blistered burn" to the operator, who told her she had first-degree burns. These types of burns don't require medical attention, and can be treated with aloe vera or Vaseline. She followed the instructions and went to bed.

She woke up at 3 a.m. with her eyes bloodshot and watering, and her face burning, comparing the pain to that of cooking burns. She took more painkillers and applied more aloe vera and went back to sleep.

In the morning, she said she couldn't even recognize herself because of how swollen her face was, so she went to the emergency room.

During her 12 hours there, she was diagnosed with chemical burns. She believes that the oils soaked into her face, and fixing the fire "ignited" a chemical reaction. She thinks washing her face didn't help since water doesn't cut through oil.

"Do the public know of the dangers of essential oils so they can assess and decide if the benefits outweigh the risks?" she wrote on Facebook.

"The way to turn our diffuser off (holding the button on the side), put me in direct risk of coming into direct contact with the vapor," she wrote. "It has a light which also turns on and off on the side, another potential hazardous feature. Is this safe?"

"I'm extremely fortunate to have my sight at all, and lucky that the burn wasn't worse, but I have suffered permanent eye damage and am potentially facially scarred for life," she continued.

For those skeptical of Smith's story, it turns out that the choice of oil could actually cause a chemical reaction with someone's skin.

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"Patchouli oil is notorious for causing what is known as a phototoxic reaction," dermatologist Joshua Zeichner told Refinery29. "If you are exposed to sunlight and that oil is on the skin, a severe burn-like reaction may occur. People commonly develop redness, burning, stinging, peeling, and even blistering."

Other oils to watch out for are citrus oils, like bergamot and lime, according to registered aromatherapist Katherine Koeppen. Plus, these reactions can take as short as a few seconds to show up to as long as a few months.

"Risks vary depending on age of the individual, the manner in which they are using the oils, their personal health history, medications taken, and their personal body chemistry," Koeppen told Woman's Day.It's always best to consult a professional if you're unsure of which oils are safe for your household.

Thankfully, Zeichner said these burns will heal without permanent scarring, which is good news for Smith, whom we hope has a full recovery.